Tailstock centers are customarily employed on lathes and other machine tools for the purpose of supporting a work piece for rotation and in such a way as to avoid development of friction, heat or wear. Particularly under high speeds of rotation, there is an increasing demand for an adapter which will accommodate different sized centers and at the same time lend greater rigidity or support to the center in order to overcome laterally applied pressure or forces when under rotation. Moreover, there is a demand for an adapter assembly which is small enough to clear other tooling and yet provide the necessary support for rotation of different sized centers within the adapter; and in this connection to facilitate rapid substitution of centers without disassembly of the adapter as well as to permit grinding of the centers when worn without removal from the adapter assembly. In the past, the approach has been to employ either relatively bulky ball bearings or conical bearings which necessitate the use of relatively large housings and do not always offer the necessary rigidity or support against laterally applied forces or loads.
Various approaches have been taken in the past to the design and mounting of tailstock centers and, for example, U.S. Pat. Nos. 2,058,322 and 2,091,864 to J. E. Kline disclose lathe center supports which are designed to permit interchangeable disposition of different centers but do not afford spaced bearing support for the centers. U.S. Pat. No. 1,700,837 to W. R. Fisher is directed to a lathe center holder which employs sets of conical bearing members in closely spaced relation to one another and permits utilization of a punch for removal of centers from the adapter assembly.
British Pat. No. 624,119 discloses a tailstock center which includes spaced conical bearing supports which will absorb thrust as well as laterally applied forces or loads but requires a relatively large housing to accommodate the adapter assembly and center. U.S. Pat. No. 2,549,613 to J. W. Lee discloses a tailstock center in which the center itself can be engaged by a rotary drive member for the purpose of grinding centers without removal from the housing.
Other representative U.S. Patents in this field are U. S. Pat. Nos. 1,338,451 to E. M. Hoover, 2,124,164 to F. A. Fritzsch, 2,144,490 to B. R. Granberg, 2,499,131 to H. J. Coles, 2,611,174 to G. H. Cote and 2,725,777 to B. A. Benson.